The United States Study of Women's Health Across the Nation (SWAN), Visit 1 Dataset 1997-1999 is part of the SWAN series: a longitudinal, epidemiologic study on the changes in health and wellbeing of middle-age women across the country. The SWAN Visit 1 Dataset 1997-1999 includes 2,881 completed interviews of women ages 40-55 out of 3,302 women initially enrolled in the study.